The world's toughest modern Christian pilgrimage leads directly to the gates of Hell.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

This singular Irish dolmen is more Frank Lloyd Wright than upright stonehenge.

Once the longest bridge in Ireland, this rusting span sits abandoned and overrun by nature.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The ruins of this monumental city founded by the first Roman Emperor are strangely overlooked by most travelers.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

Poseidon? No one seems to know.

Local lore says two enemy dragons live within these breathtaking mountain lakes.

A two thousand year old brothel uncovered in Northern Greece.

Swarms of dainty flying insects swarm into the Petaloudes Valley to get busy.

The hermits of Karoulia protect their asocial lifestyles by living on the vertical face of a treacherous precipice.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

Large collection from the 3rd millennium BCE.

A nun spent 16 years painting the stunning Celtic mural that covers the interior of this WWI memorial.

The oldest public library in Ireland.

A sacred well steeped in Pagan roots on the West Coast of Ireland.

An ancient neolithic tomb that only sees the sun twice a year.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

An unusual manor of stunning beauty, born out of a crippling disease.

Obelisks and stone pineapples in the Irish countryside.

A moody and picturesque riverside ruin overgrown with vegetation.

A remarkably intact castle that once was the largest in Ireland.